<template>
  <form class="validate-form-container">
    <slot name="default"></slot>
    <div class="submit-area" @click.prevent="submitForm">
      <slot name="submit">
        <button type="submit" class="btn btn-primary">提交</button>
      </slot>
    </div>
  </form>
</template>

<script lang="ts">
import { defineComponent, onUnmounted } from 'vue'

import mitt from 'mitt'
type ValidateFunc = () => boolean
type Events = {
  'form-item-created': ValidateFunc
}
// 实例化 mitt
export const emitter = mitt<Events>()

export default defineComponent({
  name: 'ValidateForm',
  emits: ['form-submit'],
  setup (props, context) {
    let funcArr: ValidateFunc[] = []
    const submitForm = (): void => {
      // 循环执行数组 得到最后的验证结果
      const result = funcArr.map(func => func()).every(result => result)
      context.emit('form-submit', result)
    }
    // 将监听得到的验证函数都存到一个数组中
    const callback = (func: ValidateFunc) => {
      funcArr.push(func)
    }
    // 添加监听
    emitter.on('form-item-created', callback)
    // 卸载监听
    onUnmounted(() => {
      emitter.off('form-item-created', callback)
      funcArr = []
    })

    return {
      submitForm
    }
  }
})
</script>

<style scoped>
</style>
